Madison was born in Fort Lauderdale, Florida, the daughter of Patricia Riley and Sean Madison. She has one older brother, Connor. Madison began her acting career at the age of two, appearing in commercials for Disney and OshKosh B'Gosh. She made her film debut in the 2006 comedy film Lonely Hearts.
Madison's breakthrough role came in the 2007 fantasy-adventure film Bridge to Terabithia, in which she played Sally Hurst, the best friend of the protagonist, Jess Aarons (Josh Hutcherson). The film was a critical and commercial success, grossing over $137 million worldwide.
Madison's other notable roles include Isabelle Walker in the horror film Don't Be Afraid of the Dark (2010), May Belle Aarons in the drama series Once Upon a Time (2012–2018), and Kinsey Locke in the fantasy series Locke & Key (2020–present).
In addition to her acting career, Madison is also a singer and songwriter. She released her debut EP, "New York Minute," in 2015. She has also written songs for other artists, including Selena Gomez and Demi Lovato.
Madison is a talented and versatile actress who has proven her ability to play a wide range of roles. She is sure to continue to be a successful actress for many years to come.